Oh, come on. Westphal can play M. Landry for 40 minutes. That doesn't mean he has to START him. START him over Casspi and Greene. There's more to it than that, don't you think?
Why not? Say he starts Greene and then sends him to the bench after five minutes for the rest of the game. Would that be better? And what if he starts Casspi, and then decided to go with Greene as the starter when the season starts? Then Casspi will be upset because he will feel like he is being "punished" for something, when the only thing that happened is that PW decided that Greene is a better fit in the starting lineup. Both Casspi and Greene know that one of them will be the starter in the majority of the games this season, and not Landry, so by starting Landry PW is just letting them know that he still hasn't made the decision and that any one of them could be the starter when the season begins. That way, neither of them feels penalized when the decision is actually made, and the coaching staff also gets to take a better look at Landry in the process. I think it's perfectly reasonable.